Integrated circuit technology continues to rapidly advance, with many circuit technologies being implemented using semiconductor fabrication processes. A variety of electrically conducting material is available for implementing the layers in the gates of semiconductor integrated circuits.
As is well known in the art, a silicon oxide film has been mainly used as a material of a gate insulating film in MOSFETs, and a polysilicon film has been used as a material of the gate. However, as the integration level of the semiconductor devices becomes higher, it is required that the line width of the gate and the thickness of the gate insulating film be reduced. In the case where a silicon oxide film is used as the material of the gate insulating film, if the thickness of the gate insulating film is too thin, the insulating characteristic is not stable, as the leakage current due to a direct tunneling through the gate insulating film becomes greater. Recently there has been an effort to use a high dielectric constant material having a relatively higher dielectric constant than a silicon oxide film as the material of the gate insulating film. Also, in order to minimize the polysilicon gate depletion effect, there has been an effort to use a metal gate instead of the polysilicon gate.
However, N-Metal films such as TaCx and TaSix cannot be easily deposited directly onto several substrates used for gate insulating layers, including HfO2 or TiN. Before the present invention, deposition of TaSix on any substrate required very long incubation periods to initiate deposition of the N-metal. Even after a TaSix film was obtained, it was generally rough in texture.
Therefore, there is a need to provide methods that allow for suitable N-Metal film deposition onto gate insulation substrates.